During operation of a utility vehicle, data is produced which is provided to a driver in a driver's cab on display instruments or other output devices. For example, the driver of a heavy goods vehicle having air suspension and electronic braking systems receives in addition to information on the speed and engine speed information on the system pressure (pressure in the braking system), on the axle load (via bellows pressure sensors), on the distance to rear obstructions (via proximity sensors), etc. Some of the data are transmitted directly to the display instruments in the driver's cab, and some via an in-vehicle data bus system, for instance a CAN data bus system.
The CAN data bus system, which is established throughout Europe, only allows specified data to be transferred. Specific data that only arise in a certain vehicle type and that are not yet specified for the CAN data bus are not transmitted and hence in some cases cannot be read by the driver in the driver's cab. An additional communications path between driver and vehicle is needed or at least of interest.
In a truck-trailer combination including a plurality of vehicle units, specifically tractor unit and one or more trailer vehicles, data from the trailer vehicles can be transferred to the towing vehicle via standardized interfaces, for instance via the CAN bus system or a Powerline adapter or by other means. This requires the tractor unit and the trailer vehicles to be fitted with relevant technical equipment. The data are typically brought together in an electronic control unit and made available to the data bus system. The control unit must comprise a suitable interface for the data bus system. The electrical connection that normally exists between tractor unit and trailer vehicle or between successive trailer vehicles allows only a very limited amount of CAN data to be transmitted. Again in this case, an additional communications path is necessary or at least advantageous.
Even after being parked, utility vehicles are often meant to perform actions and/or provide the driver or another operator with information. In this case, the operating person is typically outside the vehicle. A communications facility that does not require the operator to be in the driver's cab for this purpose is useful.
Mobile communications devices such as smart phones, tablet PCs and other small computers with the facility to establish and use a wireless communications connection, for instance also via WLAN (Wireless Local Area Network), are now widely established. If a vehicle is fitted with suitable technical equipment, the operator could use the smart phone to establish a connection to the vehicle and to obtain information and/or perform functions in the vehicle. What is required first is to set up a wireless connection between the smart phone and the vehicle, in which process it should be ensured that only authorized operators can establish a connection. If the intention is to actuate functions of the vehicle, it is sensible if only one authorized operator has access to the vehicle. Otherwise functions may be invoked unintentionally or in a conflicting manner.
DE 10 2012 012 565 A1 discloses connecting a smart phone to a communications unit of a vehicle via WLAN. In order to set up and authenticate the WLAN connection, the data required for this purpose (network name, network key, password) are transmitted to the smart phone via USE cable, NFC or as a QR code. The operator no longer needs to type the data into the smart phone. The document also claims the use of a Bluetooth wireless connection between smart phone and communications unit of the vehicle. The cited document DE 10 2012 012 565 A1 explains the acronyms used above (WLAN, USE, NFC, QR-Code, Bluetooth) and others.
WO 2013/124730 A1 discloses a trailer vehicle having an electronic brake control unit, which unit is connected to the CAN data bus via a standard ISO 11992 interface. A communications unit, which works as what is called a trailer access point and contains a transceiver compliant with the WLAN standard IEEE-802.11, is also connected to the CAN data bus. The trailer access point can be connected via WLAN to a smart phone or to a navigation system in a tractor unit. To avoid unintended connections, the trailer access point can keep a list of allowed numbers of potential network partners. Maintaining this list is time-consuming. A high degree of flexibility in handling different tractor units and trailer vehicles by different drivers is hence not possible.
Network devices that have been connected to one another before in a wireless vehicle network can delete the connection data needed to set up the connection and re-import the data before every connection setup, for instance by way of the aforementioned QR-code capture, or can store the connection data so that next time the connection can be set up automatically and without re-capturing the QR code. The latter option is advantageous for reasons of convenience. The situation can thereby arise in which a trailer access point establishes automatic connections to a plurality of smart phones as clients in the WLAN or in another wireless network. As long as the clients are only retrieving information, this is usually not critical. Dangerous situations can arise if an operator/driver is connected by his smart phone via WLAN to the communications unit of a vehicle and wishes to perform control functions, for instance in the sense of remote control. For this purpose, it must be ensured that the smart phone is connected to the vehicle that the driver/operator actually wishes to control remotely. A connection to another vehicle must not exist inadvertently.